A filter that functions as an artificial kidney and typically used in a haemodialysis system to remove impurities/fluid from the blood of a patient. It typically consists of cylindrical containers with thousands of longitudinally arranged hollow-fibre capillary tubes (e.g., polymer, modified cellulose) through which the blood flows. The tube walls function as a semi-permeable membrane, permitting passage of larger molecules from the blood to the dialysate on the outside of the tubes for removal. This is a single-patient, reusable device after high-level disinfection.